Masonry drill



pril-2 ,1953 H. D. G; SCHEFFER 2535,1556

MASONRY DRILL Filed May 27, 1949 INVENTOR. HARVEY D.G. SCHEFFER ATTORNEY Patented Apr. 21, 1953 UNITED "STATES PATENT OFFICE MASONRY DRILL Harvey I G. Scheffer, Westlield N, J assignor '10 Diamond Expansion Bolt Company, Garwood, N. J a corporation of New Jersey Application May27, 1949, SerialNo. 95,669

sclaims. 1 his inven en'relates-to ri l 5 5 11115 u ed i d ll .holes in mas nry- Mo epa-r ie la lntm inv nt d als, a tool o this. ty en si mploying a t cutt r of har me erieL t e eby e d r nsd ills o xthist p and ind e e ei n in o e tion F rt er. h in nti n dea ith a s i a l roo ed to k teiae l t e en omaiic splacemen o the a t el e H e ri .hole- Stil mor part u arl the i ven io dea w th a p e ale ind ne on. t e ti ende the stock t ein rce. supp r and bac t cutter p ther on- The ovel ,fea ure at theain re ie i be be nd ood :frem thei le ine de eri t e h a e to th r w ththe ee empan i dra n in h h e tian mbod men o the ,i v n are i o ed. a wi chthe s pa te a t are designated by ,suita ;e reference characters in each of the yiews; and in which:

Fi .1 is side v ew eiadri l m de e e rd ne to my invention, diagrammatically illustrating the use thereof.

Fig. 2 is. a viewlooking at the top end of the drill.

Fig. 3 is a side view of the structure as seen in Fig. 2.

Fig. 4 is a view looking in the direction of the arrow 40f Fig. 3.

Fig. 5 is a sectionon the line 5-5' of Fig. 4; and

Fig. 6 is a section onlthe broken line 0-6 of Fig. 2.

In drills of the'kind underconsideration, where a cutter tip has been disposed i pon the .endpf the drill, difficulty has been experienced in the upport of th t p, an fu ther, in guiding the drill in its movement through the workpiece. The latter has been experienced primarilyfrom the freeness of the drill' shank in the cut hole,, permitting the cutter clearance to move inthe direction of the soft spcts-in the masonry. Furthermore, the gathering of the drill cuttings or particles around the shank, prevent the drilling of deep holes, since these cuttings will pack and bind the drillto the extent that it stopsthe rotation. These cuttings also hold in the heat decreasin he cutting life of theltip.

It is the. purpose of m inyention to provide a drill of the character described wherein the shank has a spiral groove formed therein to automatically feedthe ground particles or chips out of the hole as the drill passes into the workpiece in forming the hole. .Stillimoreparticularly, the invention deals with a drill of the character described wherein the shank is ground adjacentthe cutter tip, so as to providesupportingand reinforcing walls closely adjacent the cutter edge of said tip, and further, to proyide clearance for free passage of the particles into the spiral feed groove of the drill. Another feature of the invention resides in so grinding the drill as to which is disposed approximately ninety degrees t be el ri ding f t e t ppend of the drill, as well as said cutter tip. .A further feature of the invention resides milling the drill shank to prQYide at the, bottom of the slot, angularly disposedsuhfaces forming a key portion on the shanl; for keying the cutter tip against movement rad ally e ea d sh nk,

In Fig. 1 of the drawing, l have diagrammatieell ill strate a o one .o m dri D. the end f the dri bein -sup or ed b a su di il chu k. ind ca d me t nd a u i a it El e me ed q tien 9f th r l ha k is fash o ed t m a lens s iral oove 12, tween which is a relatively flat-faced screw thread [3, which acts as a feed-screw for feedparticles or cuttings from a workpiece l4 or the hole i5 drilled therein to the surface of the workpiece, as indicated at 16. The free end of thedrill has a transverse groove or slit ll, preferably defined bydiverging walls is to form centrally of the axisof the drill a raised contracted portion] 9;

At Zil. is shown a drilltip or tool which is preferably composed of an extremely hardsubstance, such {for example, as tungsten carbide, and this tip is of a width to fit snugly in the slot or recess ii and is ,silverrsolderedlor otherwise se cured thereto. The inner endof the tip has a flat conical surface. 21, note Fig. 5, to fit snugly on the surfaces l8, thus keyin the tip or tool against lateral or radial displacement from the This construction provides a secure mounting ,of the tip Q1", tool at the end of the shank; The tip 20 has parallel side walls 22 whi h ex nd be ond h thread It, i ot wordathe tip 313 is of greater width than the outside diameter of the thread l'3, to provide c ear nce i9? @1 S -I Th out d of the tip has upwardly contracted hevelledcutter edges lewh eh t rmin a i P a e d '4; ni t in Width t an the thickness f the tip 21;, by reason of the. ground surfaces, later described.

In grinding the drill,]the tip end thereof, at epposedsiues of the u o to i ar ground to form long bevelled surfaces 25, which surfaces extend onto the threaded. portion of. the shank it]; so. as to reduce the fiiiemeter of the threads materially, at a point inwardly of and adjacent the tip 2ll, as indicated at 26, in. Fig. 6 of the drawing. This reduction of thethread provides free clearance for the ,chi'psflor out ines: to e};- tend into'the feed groove IE to displace the chips from the hole 15 in the manner indicated in Fig. 1.

13onsigcleril g' ig 2 .of the drawing, it will appear. that the ground surfaces 25 are ground at an angle to t lane et 2i; so h these surfaces 25 closely approach the side surfaces of the tip 20, as at 21, Whereas relatively tending its cutting life.

heavy stock is provided to back-up the tip 20, as at 28, the drill being rotated in the direction of the arrow 29 of Fig. 2 of the drawing.

In addition to grinding the surfaces, as at 2", the drill is ground for sharpening along the edges 23, as represented by the ground surfaces 30, these grindings extending onto the portions 28, as will appear from a consideration of the right hand side of Fig. 3, and as indicated in Fig. 4. This method of grinding disposes the end 24 of the edges 23 at a slight angle to the opposed surfaces 25, as will appear from a consideration of Fig. 2. It will also be apparent from a consideration of Fig. 3 of the drawing, that the stock of the shank it extends to a point on the tip 20 adjacent the end 24, as indicated at 3|, the stock of the shank being heaviest between 28 and 3! and relatively thin between 27 and 3|, as appearing in Fig. 3 of the drawing. In other words, the cutter edges 23 of the tip or By reason of this construction, extremely hard materials, such as tungsten carbide can be successfully used in performing drilling operations of the type and kind under consideration.

t will appear from a consideration of Fig. 6 of the drawing, that the ground surfaces 25 extend onto the tip or tool 26, as indicated at 25'. This reduces the end 24 to some extent, but still maintains a relatively wide end 2% in contrast to the pointed end usually employed in drills of this type and kind.

The ground surfaces 30 are substantially at right angles to the ground surfaces 25, and the tip end 24 extends at an angle of approximately ninety degrees to the surfaces 25. This type of sharpening permits more metal between the ground surfaces than is usually employed, thus providing more metal for heat dissipation and greater strength to the cutting edge, thus ex- With a drill of the type and kind under consideration, it will be apparent that the drill can be resharpened or reground 'to quite an extent, until most of the tip or tool 20 has been consumed. It will thus be apparent that a tool of the kind under consideration becomes highly economical in use. The thread 13 in addition to providing the feed groove 12, also provides a support and guide for the drill in the hole I of the workpiece [4 being formed, the thread guiding the tool in its passage into the workpiece. In Fig. 1 of the drawing, clearances have been exaggerated from the standpoint of clarity.

For purposes of description, the slotted end of the drill shank may be termed the drill head and the coacting conical surfaces on the base of the drill head slot and the cutter, tip or tool may be regarded as a conical key seat between the parts. On the other hand, this key construc. tion may be regarded simply as means keying the tool in the head.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A drill of the character described, comprising an elongated shank, one end portion of the shank having a spiral groove extending longitudinally thereof, said end portion of the shank terminating in a transversely slotted drill head, opposed walls of said slot being parallel, a cutter snugly and fixedly secured in the slot of said head and protruding at opposite sides of the head, said cutter having contracted outer ends 4 forming cutter edges, said cutter edges being defined by outwardly and downwardly inclined surfaces, the head end of the shank at opposed sides of the slot having substantially flat tapered side surfaces contracting in the direction of said end of the drill, and the tapered side surfaces of the shank being disposed angularly to the plane of the cutter to dispose a thick wall portion of the head at each side surface of the cutter to reinforce said cutter.

2. A drill of the character described, comprising an elongated shank, one end portion of the shank having a spiral groove extending longitudinally thereof, said end portion of the shank terminating in a transversely slotted drill head, opposed walls of said slot being parallel, a cutter snugly and fixedly secured in the slot of said head and protruding at opposite sides of the head, said cutter having contracted outer ends forming cutter edges, said cutter edges being defined by outwardly and downwardly inclined surfaces, the head end of the shank at opposed sides of the slot having substantially fiat tapered side surfaces contracting in the direction of said end of the drill, the tapered side surfaces of the shank being disposed angularly to the plane of the cutter to dispose a. thick wall portion of the head at each side surface of the cutter to reinforce said cutter, and the tapered surfaces of the head extending onto the spiral groove portion of the shank inwardly of said cutter.

3. A drill of the character described, comprising an elongated shank, one end portion of the shank having a spiral groove extending longitudinally thereof, said end portion of the shank terminatin in a transversely slotted drill head, opposed walls of said slot being parallel, a cutter snugly and fixedly secured in the slot of said head and protruding at opposite sides of the head, said cutter having parallel side surfaces and contracted outer ends forming cutter edges, said cutter edges being defined by outwardly and downwardly inclined surfaces, the head end of the shank at opposed sides of the slot having substantially fiat tapered side surfaces contracting in the direction of said end of the drill and disposed angularly to parallel side surfaces of the cutter, said cutter edges being bevelled at an .angle of approximately to the tapered side surfaces of the drill head, and the drill head having thick wall portions extending onto opposed sides of the cutter to reinforce and back the cutter.

HARVEY D. G. SCHEFFER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 994,668 Childs June 6, 1911 1,106,966 Pauli Aug. 11, 1914 1,135,530 Jopling Apr. 13, 1915 1,388,792 Bernay Aug. 23, 1921 2,101,376 Voigtlander Dec. 7, 1937 2,506,474 Tilden May 2, 1950 2,507,221 Phipps May 9, 1950 2,565,333 Weidman et a1. Aug. 21, 1951 FOREIGN PATENTS Number Country Date 375,596 Great Britain June 30, 1932 423,647 Great Britain Feb. 5, 1935 500,147 Great Britain Feb. 3, 1939 363,913 Germany Dec. 31, 1931 584,050 Germany Aug. 31, 1933 

